docs: def service(action, service_name, **kwargs):
      """Control a system service.
  
      :param action: the action to take on the service
      :param service_name: the name of the service to perform th action on
      :param **kwargs: additional params to be passed to the service command in
                      the form of key=value.
      """
      if init_is_systemd():
          cmd = ['systemctl', action, service_name]
      else:
          cmd = ['service', service_name, action]
          for key, value in six.iteritems(kwargs):
              parameter = '%s=%s' % (key, value)
              cmd.append(parameter)
      return subprocess.call(cmd) == 0